Threshold Braking or ABS: best set up for RR?
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From: Trabuco Canyon, CA
Threshold Braking or ABS: best set up for RR? I'm building a road race car out of my 240sx. I've stitch welded the chassis and just finished the mounts for my LS1 and t56. I've got a huge C&R radiator with a built in oil cooler.
But now I'm looking at my options for brake upgrades. My car came without the optional abs upgrade, and I'm debating on whether or not to retro fit the abs.
Every on track comparison of 60-0 distances I've ever seen had the abs coming out on top by a large margine. But recently I've heard "a guy" or two tell me that he learned at a driving school how to stop in a shorter distance by "threshold braking" after pulling his abs fuse.
So what do you guys think? Does ABS detract on the track?
But now I'm looking at my options for brake upgrades. My car came without the optional abs upgrade, and I'm debating on whether or not to retro fit the abs.
Every on track comparison of 60-0 distances I've ever seen had the abs coming out on top by a large margine. But recently I've heard "a guy" or two tell me that he learned at a driving school how to stop in a shorter distance by "threshold braking" after pulling his abs fuse.
So what do you guys think? Does ABS detract on the track?
While some people can brake faster without ABS, it takes a lot of effort, where as with ABS you can devote less thought to braking and more to other stuff. I would say try it without ABS and see how it drives. Adding ABS will be complicated and time consuming.
I agree with Mojave and Mitch.
How hard do you think it would be for you to retrofit the ABS? If it's not tooo much trouble I'd say do it, unless you had previous racing/tracking experience with a non-ABS car.
How hard do you think it would be for you to retrofit the ABS? If it's not tooo much trouble I'd say do it, unless you had previous racing/tracking experience with a non-ABS car.
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From: Dallas
If you got some experience with no ABS and racing tires, then staying with no ABS is understandable.
If you can lock the stickies with relative ease at speed, you might add in ABS... it'll save tires.
If ya don't, get the braking distribution down pat to how you like it. You can always reduce the pressure so you don't overreact and lock the tires when you go "oh ****!"
If you can lock the stickies with relative ease at speed, you might add in ABS... it'll save tires.
If ya don't, get the braking distribution down pat to how you like it. You can always reduce the pressure so you don't overreact and lock the tires when you go "oh ****!"
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From: Trabuco Canyon, CA
So, "the guy" was right? You can stop faster with out ABS? And if so how much effort are we talking about? The kind of effort that will take years to develop, or just a little more concentration?
I don't think that retrofitting the ABS will be too much trouble. I already plan on changeing mastercylinder (which would need to be done), then all I need are 3 speed sensors, and the module.
I don't think that retrofitting the ABS will be too much trouble. I already plan on changeing mastercylinder (which would need to be done), then all I need are 3 speed sensors, and the module.
Originally Posted by GIGAPUNK
So, "the guy" was right? You can stop faster with out ABS? And if so how much effort are we talking about? The kind of effort that will take years to develop, or just a little more concentration?
I don't think that retrofitting the ABS will be too much trouble. I already plan on changeing mastercylinder (which would need to be done), then all I need are 3 speed sensors, and the module.
I don't think that retrofitting the ABS will be too much trouble. I already plan on changeing mastercylinder (which would need to be done), then all I need are 3 speed sensors, and the module.
Learning to brake consistently and repeatably at the limit better than ABS will take time (and some flat spotted tires) to develop. I would think on the order of a year's worth of track events (just a guess). But yes, many professional and semi-professional drivers can outbrake ABS. The trick is doing it corner after corner after corner. ABS takes away all that effort, since it WILL be consistent.
I think you should drive it as it at first, and see what it actually does. If you are prone to locking tires a lot, then add the ABS. If you can drive at the limit without locking tires, then spend the time/money elsewhere. Just because some person in some car is better with or without ABS doesn't mean you will in your car with your brake and tire setup.
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From: Miami
Generally, I don't trigger ABS at the track unless I've overcooked a brake zone. It works like a parachute for me (but then again, I'm running in a street car with street tires with street/track pads).
Threshold braking done properly gets the tire to "chatter" at a point just before lock-up (at the threshold of lock-up- thus the name). It's basically a human version of ABS. No ABS is fine. Many people end up using it as a crutch.
Threshold braking done properly gets the tire to "chatter" at a point just before lock-up (at the threshold of lock-up- thus the name). It's basically a human version of ABS. No ABS is fine. Many people end up using it as a crutch.
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From: College Station, TX
It does take a lot of training to do it, but it's worth it. Want a car that drives itself or do you wanna drive? Want a car that brakes itself or do you wanna brake?
I know how fast my pickup will stop. This was about a 65-0mph stop. I probably would have beaten the abs stopping distance. There's a price though, my wheels locked at first, my eyes went crossed and all my adrenaline and focus went into my right foot. The brakes were at the edge of locking the rest of time. I'd rather trust myself, but I need some training so that I don't lose focus on the road next time.
If you're locking stickies, you really need to train.
I know how fast my pickup will stop. This was about a 65-0mph stop. I probably would have beaten the abs stopping distance. There's a price though, my wheels locked at first, my eyes went crossed and all my adrenaline and focus went into my right foot. The brakes were at the edge of locking the rest of time. I'd rather trust myself, but I need some training so that I don't lose focus on the road next time.
If you're locking stickies, you really need to train.
I don't know how hard it would be to add your ABS, or how good the ABS is on a 240SX. Can a human outbrake an ABS system...it depends. There are some abs systems that aren't to great (early 90s gm for example). And there are drivers that are better than others.
Assuming the ABS for you car is capable, I doubt you could consistantly outbrake the ABS. Are you going to be at the top of your game on every corner on every track?
Another factor is ease of install. Its probly good advise to try as is and see if you feel you need it then. But thinking not having ABS is a performance advantage is probly wishful thinking.
Assuming the ABS for you car is capable, I doubt you could consistantly outbrake the ABS. Are you going to be at the top of your game on every corner on every track?
Another factor is ease of install. Its probly good advise to try as is and see if you feel you need it then. But thinking not having ABS is a performance advantage is probly wishful thinking.
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From: Trabuco Canyon, CA
Originally Posted by subtlez28
...But thinking not having ABS is a performance advantage is probly wishful thinking.
And if I "really want to drive," or find it distracting on the track I can always pull the fuse right?
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From: MA
Originally Posted by GIGAPUNK
So what do you guys think? Does ABS detract on the track?
That means if you find yourself spinning on track you put in the clutch (so you don't stall) and you lock up the brakes so that you can control the direction you are going.
With ABS, in a spin you have no idea where you will end up. Just remember to apply the brakes smoothly and you will learn how to drive and be much safer on the track.
(oh yeah, awesome project, post pics!!!)
Last edited by SHELBYGLHS; Jul 5, 2007 at 02:05 PM. Reason: more info
Curious>>>> what mean for Threshold Braking ?
I am working on my Camaro w/LS2 Carburator/M6 manual. I think about about remove the ABS. I have been figure out how it works without ABS. Should leave my OEM brake booster /master cylinder. Big concern about vaccum brake beside brake booster?
I found out that my LS2 Carb. not need to have vaccum.
Suggestion?
I am working on my Camaro w/LS2 Carburator/M6 manual. I think about about remove the ABS. I have been figure out how it works without ABS. Should leave my OEM brake booster /master cylinder. Big concern about vaccum brake beside brake booster?
I found out that my LS2 Carb. not need to have vaccum.
Suggestion?
Threshold braking is maintaining the car on the
threshold of tire slip by control of brake pedal
pressure.
Static (stuck) friction is always higher than sliding.
ABS backs off pressure once slip is sensed, then
restores it, backs it out, etc. This means you spend
some time in slip but break it off. Better than staying
locked in slip. But, someone who can maintain the
car just short of losing adhesion gets to take advantage
of full-time, static friction.
This is tough to really do when you have four wheels
with different, changing loading but a single brake
pressure input. Odds are one tire is doing more work
than the rest and you have to baby that one. Like
braking into a turn, outside front gets extra down-
force it can't use with a brake line pressure that
won't lock the inside rear.
4-wheel ABS, stomp the pedal, all 4 get controlled
individually to near-threshold (+/-, chop, repeat) so
in any unbalanced situation ABS will kick ***, apply
maximum usable pressure to each corner.
So theoretically a good driver in a controlled or
anticipated (setup and event) situation could beat
the ABS but for random **** comes your way, the
ABS is more reliably going to win. Takes a lot of
practice to turn your panic reflex into instinctive
threshold braking and without the freedom to
apportion brake pressure to where it does the most
good, in the moment, threshold braking can still
come in second-best.
threshold of tire slip by control of brake pedal
pressure.
Static (stuck) friction is always higher than sliding.
ABS backs off pressure once slip is sensed, then
restores it, backs it out, etc. This means you spend
some time in slip but break it off. Better than staying
locked in slip. But, someone who can maintain the
car just short of losing adhesion gets to take advantage
of full-time, static friction.
This is tough to really do when you have four wheels
with different, changing loading but a single brake
pressure input. Odds are one tire is doing more work
than the rest and you have to baby that one. Like
braking into a turn, outside front gets extra down-
force it can't use with a brake line pressure that
won't lock the inside rear.
4-wheel ABS, stomp the pedal, all 4 get controlled
individually to near-threshold (+/-, chop, repeat) so
in any unbalanced situation ABS will kick ***, apply
maximum usable pressure to each corner.
So theoretically a good driver in a controlled or
anticipated (setup and event) situation could beat
the ABS but for random **** comes your way, the
ABS is more reliably going to win. Takes a lot of
practice to turn your panic reflex into instinctive
threshold braking and without the freedom to
apportion brake pressure to where it does the most
good, in the moment, threshold braking can still
come in second-best.
Last edited by jimmyblue; Jul 11, 2007 at 03:47 PM.
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From: Trabuco Canyon, CA
Jeff, one of the rasons that I',m trying to plan this out now is because the ABS requires a totally different master cylinder.
Shelby, glad you dig the pics! Project's gunna be a little slow this month, but a new welder is on the way! Stay tuned.
Everyone else... I'm still confused. Especially since this car will see double duty on the road course and street, and since I'm willing to put in the time to becoming the best driver that I can be.
Shelby, glad you dig the pics! Project's gunna be a little slow this month, but a new welder is on the way! Stay tuned.
Everyone else... I'm still confused. Especially since this car will see double duty on the road course and street, and since I'm willing to put in the time to becoming the best driver that I can be.
Originally Posted by Jeff Smith
Curious>>>> what mean for Threshold Braking ?
I am working on my Camaro w/LS2 Carburator/M6 manual. I think about about remove the ABS. I have been figure out how it works without ABS. Should leave my OEM brake booster /master cylinder. Big concern about vaccum brake beside brake booster?
I found out that my LS2 Carb. not need to have vaccum.
Suggestion?
I am working on my Camaro w/LS2 Carburator/M6 manual. I think about about remove the ABS. I have been figure out how it works without ABS. Should leave my OEM brake booster /master cylinder. Big concern about vaccum brake beside brake booster?
I found out that my LS2 Carb. not need to have vaccum.
Suggestion?
91 Camaro RS w/ new 350 motor/trans., run 325 rhp
2001 Camaro SS with no LS1. -
Working on 2001 Camaro with LS2 w/o PCM| SLP Creamic Headers| 830 CFM Holley Double Pump| Distributor|T-56
'03 Chevy CrEw CaB DuraMax (tOW )"
WTF!?!
I realize people type fast, and mispell (or miss all together) words on forums, but this is horrible.
Not to be a complete @$$, but is english your 4th language or something?
*Sorry, I realize this is off topic...but holy crap!*
